Abstract

Yb-doped femtosecond fiber chirped pulse amplifiers (FCPAs) are extremely attractive to replace their solid-state counterparts in when it comes to robustness and ease of operation. However, in most Yb-doped FCPAs delivering high-energy output pulses the advantages of robustness and ease of operation are forfeited since free-space optical components are used to stretch and compress the pulses. The main bottleneck to obtain fiber based stretching and compression is to match the dispersion of the stretcher and compressor. Recent advances have yielded good results with fiber-based stretchers and free space compressors [1–3]. However, the free space compressors require rather large distances between the compressor elements, which reduces the robustness of the system. On the other hand, while anomalous dispersion solid-core fibers have been available, e.g. photonic crystal fibers [4] or higher-order mode fibers [5], such fibers are not suitable as compressor fibers for pulse energies exceeding several nJ, because of the high nonlinearities experienced in the solid core. The use of a hollow-core (HC) photonic bandgap fiber (PBF) can alleviate this problem, an approach that was demonstrated in Er-doped fiber lasers [6]. Short lengths of HC PBF have been used to compress pulses from Yb-fiber oscillators [7], but not yet in Yb-FCPA. Here, we present a μJ-level femtosecond Yb-FCPA that uses a dispersion-matched dispersion compensating fiber (DCF) stretcher [8] and a HC PBF compressor.

© 2013 IEEE